Nowadays, telecommunication networks are rapidly changing with the increasing use of multimedia applications over fixed and wireless networks. Multimedia applications include voice over Internet protocol (VoIP) applications, video conferencing, and messaging. VoIP is a technology that allows voice calls to be transmitted via the Internet, using a broadband connection. VoIP calls can be made over a wireless network by using a VoIP service provider. While a VoIP call connection is being made, the call needs to traverse through multiple IP networks. As a result, VoIP service providers supporting IP peering capabilities need to support high-layer application-level protocols for services such as VoIP. Session Initiation Protocol (SIP) is one such application-layer control protocol that addresses call set up and termination, error handling, and interprocess signaling. SIP also initiates, modifies, and terminates multimedia sessions, including conferences, Internet telephony, distance learning, and other applications.
There are a number of inter-carrier network problems that arise when voice calls are transferred between IP networks. Specifically, issues pertaining to media coder-decoder (codec) incompatibility between the source and destination of VoIP become a problem in larger cross-carrier networks. Due to the complex interconnection between networks, support for media and codec transcoding functions is essential.
As the use of VoIP becomes more widespread, service providers are required to support different types of VoIP media streams, which include uncompressed and compressed codecs. Different types of VoIP media streams have a different voice quality. To support different types of VoIP media streams, transcoders are required to convert media stream from one format to another. Two key aspects are associated with a transcoder—resource usage for transcoding, and resource usage for storing. The resource usage for transcoding relates to the use of bandwidth and the number of channels required to support each media type in the call. Hence, it is important for the service providers to optimize the use of transcoder resources while maintaining a good voice quality.
Elements in the Figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Furthermore, the terms “first”, “second”, and the like herein, if any, are used inter alia for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. Any of the preceding terms so used may be interchanged under appropriate circumstances such that various embodiments of the invention described herein may be capable of operation in other configurations and/or orientations than those explicitly illustrated or otherwise described.